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authorYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>2013-02-23 04:32:56 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-24 05:50:12 +0400
commit46c66c4b7ba0f9bb3e2ae3a3cfd40cd3472c8f80 (patch)
treeeb33a350aab3adae19a91a6e63918df1a3904585 /mm/memory_hotplug.c
parentbbc76be67c2c0c12548937a07ea3643c32a95b8c (diff)
downloadlinux-46c66c4b7ba0f9bb3e2ae3a3cfd40cd3472c8f80.tar.xz
memory-hotplug: remove /sys/firmware/memmap/X sysfs
When (hot)adding memory into system, /sys/firmware/memmap/X/{end, start, type} sysfs files are created. But there is no code to remove these files. This patch implements the function to remove them. We cannot free firmware_map_entry which is allocated by bootmem because there is no way to do so when the system is up. But we can at least remember the address of that memory and reuse the storage when the memory is added next time. This patch also introduces a new list map_entries_bootmem to link the map entries allocated by bootmem when they are removed, and a lock to protect it. And these entries will be reused when the memory is hot-added again. The idea is suggestted by Andrew Morton. NOTE: It is unsafe to return an entry pointer and release the map_entries_lock. So we should not hold the map_entries_lock separately in firmware_map_find_entry() and firmware_map_remove_entry(). Hold the map_entries_lock across find and remove /sys/firmware/memmap/X operation. And also, users of these two functions need to be careful to hold the lock when using these two functions. [tangchen@cn.fujitsu.com: Hold spinlock across find|remove /sys operation] [tangchen@cn.fujitsu.com: fix the wrong comments of map_entries] [tangchen@cn.fujitsu.com: reuse the storage of /sys/firmware/memmap/X/ allocated by bootmem] [tangchen@cn.fujitsu.com: fix section mismatch problem] [tangchen@cn.fujitsu.com: fix the doc format in drivers/firmware/memmap.c] Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Julian Calaby <julian.calaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e5b91b12cec3..a776dbf3fa00 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1460,7 +1460,7 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
return ret;
}
-int remove_memory(u64 start, u64 size)
+int __ref remove_memory(u64 start, u64 size)
{
unsigned long start_pfn, end_pfn;
int ret = 0;
@@ -1510,6 +1510,9 @@ repeat:
return ret;
}
+ /* remove memmap entry */
+ firmware_map_remove(start, start + size, "System RAM");
+
unlock_memory_hotplug();
return 0;